2022-10-10 15:47:06 -05:00
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.global find_first_card
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2022-10-09 12:01:12 -05:00
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2022-10-10 15:47:06 -05:00
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| Finds the first card with the type in d0.b, and returns it's IO base address in a0, or 0 if not found
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| Clobbers d1
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find_first_card:
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move.l #0xff0000, a0 | a0 holds the address of the current card
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ffc_loop:
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lea (0x100, a0), a0 | adda.l #$100, a0 | Move to the next card
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move.b (0xff, a0), d1 | Load the type of the card into d1
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beq.b ffc_done | If the type is 0 (empty slot), we have scanned all cards, so exit the loop
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cmp.b d0, d1 | If the card is the type we want, return with the address in a0
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beq.b ffc_done
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bra.b ffc_loop | Loop back and check the next card
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ffc_done:
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rts
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